The quarter-inch CMOS implies worse low-light performance compared to previous Canon HD models, as sensitivity is directly related to the area collecting light from the lens. Although image processing can compensate for this, with the JVC Everio GZ-HD300 punching above its weight for this reason, in the HF20's case the compromise is clear.
As illumination drops, much more grain becomes visible than with Canon camcorders sporting larger sensors. This noise is also more multicoloured, increasing its intrusiveness. With most other Canon HD camcorders, switching to progressively scanned 25pf mode helps this a little, as it enables a 1/25th shutter speed. With the HF20, however, there is little discernible difference between the two.
Fortunately, the HF20 saves itself in better lighting. Here, performance is every bit as good as previous models. Colours are rich and vibrant - and if you prefer a less saturated look you can always dial this back with the Image Effects. Fine details are clearly visible, and scenes of high contrast are resolved without blowing out bright areas or losing gradation in shadows. So the HF20 will provide pleasing results in many situations - just not when the lights dim too much.
When it comes to editing, there will be few problems, as the AVCHD format is now supported by all mainstream PC editing apps, as well the most recent versions of Apple's iMovie. If you merely want to watch your footage straight on your HDTV, the HF20 offers mini-HDMI, although as usual without an adapter supplied for use with the full-sized HDMI on TVs. The HDMI output complies with version 1.3, so transfers x.v.Color if supported by your TV. Alternatively, there's a proprietary connection for analogue component output at 576i or 1080i, and the headphone jack can be switched to output composite video.
So the Canon Legria HF20 doesn't top the quality charts like previous Canons, although it is still very good. This would be fine if it was a lot cheaper in compensation. Canon's 2008 models didn't translate their technical excellence into total sales dominance, thanks to cheaper models from competitors, in particular Panasonic's HDC-SD9. Unfortunately, the weakness of the pound has foiled Canon's plans. The Legria HF20 is no cheaper than the HF11 was at launch, and the latter will shoot better video in low light. For this reason, if you can find the HF11 for less than the HF20, or the HF100 for considerably less, both would be better value.